Plasm etching device

ABSTRACT

A plasma etching device using radio frequency electromagnetic energy to produce the plasma comprises a plasma reaction cavity and a rotary access device; the plasma reaction cavity has a substrate reaction disc and a radio frequency parallel electrode board therein; the substrate reaction disc is circular in shape; the rotary access device is adjacent to the plasma reaction cavity for placing a substrate that requires processing into the plasma reaction connect chamber; the substrate is placed into or removed from the narrow and small sealed connect chamber in the plasma reaction cavity by the rotary access device.

FIELD OF INVENTION

[0001] The present invention relates to a plasma etching device, more particularly to a continuous vacuum plasma etching system that uses a ring-shaped parallel board of a plasma reaction cavity to produce extra induced electromagnetic plasma, and uses a small and narrow vacuum connect chamber to move substrates back and forth in/out of the atmosphere, and thus greatly reducing the operating time of accessing the substrate.

BACKGROUND OF THE INVENTION

[0002] Etching is a manufacturing process of removing materials from a substrate surface in order to meet the requirements of a design, and etching can be divided into wet etch and dry etch. The wet etch uses chemical solutions to dissolve materials from the substrate surface to meet the requirements of components or circuits. However, the wet etch has the shortcomings of an isotropic etching. If the size is reduced to less than 3 microns, the wet etch will not able to complete the etching process. Wet etch is also called plasma etching, which uses gaseous chemical etchants to produce chemical reactions or physical collisions. The etching material and the volatile by-product are removed by a vacuum pump. Since plasma can produce free radicals, these free radicals will increase the speed of physical and chemical reactions and enhance the etching. Furthermore, plasma etching does not have the isotropic problem. Therefore, dry (plasma) etch is widely used for the etching procedure of the semiconductor manufacturing process.

[0003] The common methods of producing plasma are divided into the following types:

[0004] (1) Direct current (DC) potential system: Most physical vapor deposition systems use DC to produce plasma as disclosed in the U.S. Pat. No. 5,733,419.

[0005] (2) Microwave: The activation of microwave with frequency of 2.45 GHz will provide ionizations and electrochemical reactions, which is generally used for microwave plasma enhanced chemical vapor deposition (MPCVD) as disclosed in the U.S. Pat. No. 6,423,924.

[0006] (3) Radio Frequency (RF): The plasma source with radio frequency of 13.56 MHz is common in the semiconductor manufacturing process, which uses two parallel electrodes to pass the radio frequency high-voltage electricity and produce AC electric field between the parallel electrodes. Free radicals are accelerated by means of the effect of the AC electric field until the free electron collide with the atom or molecule in the reaction chamber to produce an ion and another free electron. Since the ionic collision involves a series of reactions, therefore the whole reaction chamber is filled with equal number of electrons and ions (i.e. filled with plasma) as disclosed in the U.S. Pat. No. 5,766,404.

[0007] (4) There are some researchers who use radio frequency together with permanent or electromagnetic field to increase the production of plasma.

[0008] However, no matter which one of the aforementioned methods is used to produce plasma, the biggest problem of applying plasma on etching process is that such operation cannot be operated continuously. Most plasma reaction cavities have electrodes and substrate placing areas, and the air of the whole reaction cavity must be extracted to produce plasma for carrying out the etching procedure. Then, the process for the whole reaction cavity to change its vacuum condition back to the atmospheric condition to replace substrates is a batch reaction. Such arrangement not only makes the manual operation complicated, but also cannot shorten the manufacturing time.

SUMMARY OF THE INVENTION

[0009] The primary objective of the present invention is to solve the aforementioned problems and eliminate the drawbacks of cited prior art. The present invention discloses a circular continuous plasma method and device, which can greatly shorten the time required for the operation.

[0010] To achieve the foregoing objective, the plasma etching device according to the present invention using the radio frequency method to produce plasma comprises a plasma reaction cavity and a moving device; the plasma reaction cavity has a substrate reaction disc and a radio frequency electrode, and the substrate reaction disc is in circular shape; the moving device is adjacent to the plasma reaction cavity for placing a substrate that requires processing into the plasma reaction connect chamber; and the substrate is placed into the plasma reaction cavity. The arrangement for the moving device placing the substrate into the plasma reaction area constitutes a continuous plasma reaction system; together with a ring-shaped radio frequency parallel electrode board producing a radio frequency electromagnetic effect can increase the production of plasma.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective diagram of the appearance of the present invention.

[0012]FIG. 2 is an enlargement of part of the structure of the present invention.

[0013]FIG. 3 is a flow chart of the manufacturing procedure of the present invention.

[0014] FIGS. 4A˜4H are illustrative diagrams showing the motions of the operation of the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Please refer to FIGS. 1 and 2 for the perspective diagram of the appearance and the enlargement of part of the structure of the present invention respectively. In the figures, the present invention discloses a plasma etching device that uses the radio frequency method to produce plasma for etching, and the plasma etching device comprises a plasma reaction cavity 10 being constantly maintained in a vacuum condition, and a rotary access device 20 adjacent to the plasma reaction cavity 10, and the plasma reaction cavity 10 has a circular substrate reaction disc 11 and a ring-shaped radio frequency parallel electrode board 12 therein; the substrate reaction disc 11 is used to place the substrate 30, and the radio frequency electrode 12 provides the energy for producing plasma; the plasma reaction cavity 10 comes with a pump 13; the air in the plasma reaction activity 10 and the sealed connect chamber 40 are extracted till they are vacuum in order to carry out the follow-up etching process. During a plasma etching, besides the energy produced by the radio frequency parallel electrode 12, the ring-shaped radio frequency electrode 12 also produces an induced radio frequency magnetic field, and the production of plasma can be increased by such magnetism. The rotary access placing device 20 is a robotic arm for placing the substrate 30 that requires processing into the connect chamber 40, and the rotary access device 20 will place the unprocessed substrate 30 into the connect chamber 40.

[0016] Please refer to FIGS. 3, 4A˜4H for the illustrative diagrams of the flow and operating motions. In the figures, the present invention is a plasma etching method using radio frequency to produce plasma for etching, comprises the steps of:

[0017] (a) Loading substrate 1: using a rotary access device 20 to put a substrate 30 that requires processing into a connect chamber 40, and the substrate 30 is placed into a substrate placing area of the connect chamber 40, and a push unit 42 disposed under the substrate placing area 41 to control the elevation of the substrate placing area 41;

[0018] (b) Sealed connect chamber 2: descending the lid 43 of the connect chamber 40 after the substrate 30 is placed into the connect chamber 40, and the lid has a valve 44 externally connected to the pump 13 for extracting the gas in the connect chamber 40 of the substrate 30 until the connect chamber is in a vacuum;

[0019] (c) Sending substrate into the plasma reaction cavity 3: After the connect chamber 40 is sealed, the substrate placing area 41 containing a substrate 30 is descended by a push unit 42 until the substrate placing area 41 and the circular substrate reaction disc 11 are of the same level, and then the substrate 30 uses a rotary unit 14 under the circular substrate reaction disc 11 to enter into the plasma reaction area 12 having parallel radio frequency electrodes 12 in a rotary manner, and the radio frequency electrode 12 provides the electric power for producing plasma and processing the substrate 30 by plasma; the radio frequency electrode 12 in the plasma reaction cavity 10 is in a circular shape in order to produce the radio frequency magnetic field and increase the production of plasma;

[0020] (d) Pushing out substrate 4: using a push unit 42 to push the previous substrate in the substrate placing area 41 up and out of the circular substrate reaction disc 11 and then enter into the connect chamber 40; the substrate 30 at this point of the cycle has finished the etching;

[0021] (e) Opening the connect chamber 5: sealing the valve 44 and injecting air to resume the condition of atmospheric pressure in the connect chamber 40, and at that time the plasma reaction cavity 10 remains in the vacuum condition to lift the lid 63 of the connect chamber 40 to open the connect chamber, and uses the rotary access device 20 to take out the etched substrate 30, while placing another substrate that requires processing into the connect chamber.

[0022] In view of the description above, the present invention has the following advantages:

[0023] (1) The structure of the plasma reaction connect chamber and the rotary access device according to the present invention enables the plasma etching process to process in a continuous fashion and improves the shortcoming of the prior art that can only etch in batches. Therefore, this invention can greatly shorten the manufacturing time and improving the production efficiency.

[0024] (2) The distance between the circular plasma reaction disc and the ring-shaped radio frequency parallel electrode according to the present invention is very small, which can enhance the production of plasma. Furthermore, the radio frequency electrode in circular shape together with the induced magnetic field effect can further improve the production of plasma.

[0025] (3) Since this invention makes use of the rotary method to place the substrate into the plasma reaction area, therefore the substrates can be moved reciprocally between the conditions of vacuum and atmospheric pressure in a very short time, and thus allowing the substrate to enter and exit the connect chamber rapidly.

[0026] However, while the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims for the plasma production method primarily used in a design for the continuous operation that works together with various plasma production methods such as DC, and microwave, etc, therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures. 

What is claimed is:
 1. An etching device using a radio frequency method to produce plasma for etching, characterized in that: a plasma reaction cavity, having a circular substrate reaction disc and a ring-shaped radio frequency parallel electrode; a rotary access device adjacent to said plasma reaction cavity, for respectively placing and removing a substrate that requires processing into and from a plasma reaction connect chamber; thereby said rotary access device continuously placing another substrate into a vacuum plasma reaction area to constitute a continuous plasma reaction cavity together with a ring-shaped radio frequency parallel electrode capable of generating an induced radio frequency electromagnetic effect to enhance the production of plasma.
 2. The etching device of claim 1, wherein said plasma reaction cavity comprises a rotary unit.
 3. The etching device of claim 1, wherein said plasma reaction cavity comprises a pump.
 4. The etching device of claim 1, wherein said rotary access device is a robotic arm. 